Molded product for light-sensitive material, light-sensitive material package and production process therefor

ABSTRACT

A molded product for a light-sensitive material has a component ratio by weight of paper-derived cellulose fibers to the total of thermoplastic resins in the range of 51:49 to 75:25 and includes at least one antioxidant, and at least one aldehyde-neutralizing agent. A light-sensitive material package is formed from the molded product and a light-sensitive material that is used with the molded product. Furthermore, a process for producing the molded product includes mixing a thermoplastic resin having a melt flow rate of at least 15 g/10 min. with pellets formed by breaking, compressing and granulating a base paper produced for printing paper, so that the component proportions are 51 to 75 parts by weight of paper-derived cellulose fibers and 49 to 25 parts by weight of the total of the thermoplastic resins, and then molding the mixture at a cylinder temperature of 180° C. or less.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a molded product for alight-sensitive material, the molded product being represented by, forexample, a container for housing a light-sensitive material such asphotographic film or printing paper, and including a member that is usedfor storing a roll of light-sensitive material, etc.; a light-sensitivematerial package that is formed from the molded product and alight-sensitive material that is used together with the molded product;and a production process therefor.

[0003] 2. Description of the Related Art

[0004] In current molded products for light-sensitive materials,thermoplastic resins such as polystyrene (PS), polypropylene (PP), andpolyethylene (PE) are widely used for their photographic properties,strength, etc. When such thermoplastic resins are used in moldedproducts for light-sensitive materials, a large environmental burden isimposed when they are disposed of after use. Reducing this environmentalburden is an urgent task. As one substitute, a paper/resin mixture(hereinafter, also called a ‘paper resin’) in which the proportion ofpaper in the mixture exceeds 50 wt % is attracting attention.

[0005] With regard to the paper resin, a paper resin employing recycledpaper or waterproof paper for printing paper in which both surfaces of abase paper are laminated with a polyolefin resin, that is to say, ‘WP(waterproof) paper’, has been disclosed; for example, JapaneseRegistered Patent No. 3007880 discloses paper resin pellets obtained bybreaking recycled paper from horse-racing tickets, magazines, etc. (orWP paper) into a flock state, then mixing it with a polyolefin elastomerand making it into paper pellets by rotary compression, then blendingwith a desired resin such as PP, and processing it in an extrusionmolding machine. Furthermore, JP-A-11-99522 (JP-A denotes ‘Japaneseunexamined patent application publication’) also discloses a process forobtaining paper resin pellets in a similar manner to the above. However,it has been found that when these paper resin pellets are applied to amolded product for a light-sensitive material, for example, a moldedproduct for a roll of light-sensitive printing material (a flange, acore cap, a molded cushioning material, etc.) or a molded product for alight-sensitive material for a color copier, the photographicproperties, in particular the sensitivity, are degraded.

BRIEF SUMMARY OF THE INVENTION

[0006] The present invention has been carried out in view of theabove-mentioned circumstances.

[0007] It is an object of the present invention to provide a moldedproduct for a light-sensitive material that does not degrade thephotographic properties, has good mechanical properties, and imposesless environmental burden. It is another object of the present inventionto provide a light-sensitive material package comprising the moldedproduct for a light-sensitive material and a light-sensitive materialthat is used together with the molded product. It is yet another objectof the present invention to provided a process for producing theabove-mentioned molded product for a light-sensitive material. The‘mechanical properties’ referred to here include the rigidity thatprevents the deformation of an opening due to high speed air transfer.

[0008] The above-mentioned objects of the present invention have beenaccomplished as follows.

[0009] One aspect of the present invention provides the following meansto solve the problem.

[0010] A molded product for a light-sensitive material having acomponent ratio by weight of paper-derived cellulose fibers to the totalof thermoplastic resins in the range of 51:49 to 75:25, comprising atleast one antioxidant and at least one aldehyde-neutralizing agent.

[0011] Another aspect of the present invention provides the followingmeans to solve the problem.

[0012] A light-sensitive material package comprising a molded productfor a light-sensitive material, and a light-sensitive material that isused with the molded product, the molded product for a light-sensitivematerial having a component ratio by weight of paper-derived cellulosefibers to the total of thermoplastic resins in the range of 51:49 to75:25 and comprising at least one antioxidant and at least onealdehyde-neutralizing agent.

[0013] Yet another aspect of the present invention provides thefollowing means to solve the problem.

[0014] A process for producing a molded product for a light-sensitivematerial comprising, in the following order, steps of mixing athermoplastic resin having a melt flow rate of at least 15 g/10 min.with pellets formed by breaking, compressing and granulating a basepaper produced for printing paper, so that the component proportions are51 to 75 parts by weight of paper-derived cellulose fibers and 49 to 25parts by weight of the total of the thermoplastic resins, and moldingthe mixture with a molding machine at a cylinder temperature of 180° C.or less.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0015]FIG. 1 is an exploded perspective view of a molded product for alight-sensitive material, which is one embodiment of the presentinvention.

[0016]FIG. 2 is a conceptual view of one example of the molded productfor a light-sensitive material of the present invention.

[0017]FIG. 2 (A) is an exploded perspective view of a package, and FIG.2 (B) and FIG. 2 (C) are perspective views of a cushioning material fromdifferent directions.

[0018]FIG. 3 is a perspective view of a molded product for alight-sensitive material, which is one embodiment of the presentinvention, and which is a container wherein a body and a lid areintegrally molded.

[0019]FIG. 4 is a cross section showing a stationary disc and a rotarydisc of one example of a refiner that can be used in a fiberizing stepof the process for producing a molded product for a light-sensitivematerial of the present invention.

[0020]FIG. 5 is a lateral cross section of the example of the refinerthat can be used in a fiberizing step of the process for producing amolded product for a light-sensitive material of the present invention.

[0021]FIG. 6 shows one example of a breaking machine that is used in arough breaking step of the process for producing a molded product for alight-sensitive material of the present invention.

[0022]FIG. 7 is a cross section at line I-I in FIG. 6. DETAILEDDESCRIPTION OF THE INVENTION

[0023] The ‘total of the thermoplastic resins’ referred to in thepresent invention denotes the total of the polyolefin resin with whichthe waterproof paper for printing paper is laminated and all thethermoplastic resin that is added during a production process. In thecase where a lining layer is provided, the ‘total of the thermoplasticresins’ includes a thermoplastic resin used for the lining layer.

[0024] Furthermore, the light-sensitive material package comprises amolded product for a light-sensitive material and a light-sensitivematerial that is used together with the molded product. In the casewhere the molded product for a light-sensitive material is a container,a light-sensitive material can be housed therein to give alight-sensitive material package.

[0025] The above-mentioned aspects of the invention have beenaccomplished as a result of an intensive investigation by the presentinventors with the aim of minimizing the decomposition of cellulose bymolding at as low a temperature as possible, searching for an additivefor suppressing the decomposition of cellulose, and chemicallyneutralizing trace amounts of cellulose decomposition products.

[0026] The above-mentioned objects, other objects, features, andadvantages of the invention will become clear from the followingdescription.

[0027] Materials for the molded product for a light-sensitive materialof the present invention and representative production steps thereforare explained in detail below.

[0028] With regard to the base paper that can be used in the moldedproduct for a light-sensitive material and the light-sensitive materialpackage of the present invention, plant cellulose fiber, which isgenerally sold as pulp, can be used. Examples of starting materials usedfor the pulp include softwoods such as pine, cedar, and Japanesecypress, hardwoods such as beech, oak, and eucalyptus, and non-woodfibers such as Edgeworthia chrysantha and bamboo.

[0029] In order to conserve forestry resources, much attention has beenpaid to the reuse of paper resources, and it is also possible to useplant cellulose fiber that has been regenerated as recycled pulp bysteps such as fiberizing, coarse screening, aging, deinking, finescreening and bleaching using recovered paper collected from domestic,business, and public transport premises, including newspapers, weeklypublications, magazines and advertising handouts, and refuse and brokefrom binding and printing factories.

[0030] In the present invention it is preferable to use, asbase-paper-derived cellulose fiber, a base paper produced for printingpaper and/or a waterproof paper for printing paper obtained bylaminating the base paper with a polyolefin resin.

[0031] In the present invention, the ‘base paper produced for printingpaper’ refers preferably to a base paper that can be broken intocellulose fibers having a weight-average fiber length in the range of0.30 to 0.50 mm. With regard to such a base paper, a base paper madefrom kraft pulp, etc. can be cited, and it is often used for printingpaper, but a base paper that is used for other purposes can also beincluded in the ‘base paper produced for printing paper’ of the presentinvention as long as the aforementioned requirement for fiber length issatisfied. The weight-average fiber length can be measured using anoptical measurement device such as that described in the examples below.The weight-average fiber length changes little from the value measuredimmediately after breaking to that measured during the molded productproduction process.

[0032] The ‘base paper produced for printing paper’ used in the presentinvention is preferably formed using hardwood bleached kraft pulp whosecellulose fibers, before the base paper is broken, have a weight-averagefiber length in the range of 0.4 to 0.7 mm. A waterproof paper forprinting paper obtained using the above-mentioned base paper is brokenusing a refiner, a pin mill etc. and the cellulose fibers thus obtainedparticularly preferably have a weight-average fiber length in the rangeof 0.30 to 0.50 mm as described above. When the weight-average fiberlength of the cellulose fibers before breaking exceeds 0.7 mm, thekneadability with a resin tends to be degraded, and the kneading tendsto require a high temperature of at least 250° C. and a long duration.When the fiber length is less than 0.4 mm, although it becomes possibleto knead at a comparatively low temperature less than approximately 220°C. for a short time, the precision and strength of the paper resinmolded product so obtained tend to be degraded. Use of a base paperemploying cellulose fibers having a weight-average fiber length in therange of 0.4 mm to 0.7 mm before breaking can give a paper resin moldedproduct having high surface smoothness, high molding precision, and highmolding strength.

[0033] The length of the cellulose fibers is preferably uniform. Auniform length for the cellulose fibers allows the kneading step and themolding step in the paper resin molded product production process to becarried out uniformly and robustly. Furthermore, the time required forthese steps can be shortened, thereby preventing excessive thermalenergy being applied and minimizing the adverse effects on thephotographic properties from the paper resin molded product so obtained.

[0034] The ‘base paper produced for printing paper’ used in the presentinvention is preferably formed using a hardwood (laubholz) bleachedkraft pulp (LBKP) as a starting material. A method for paper makingusing an LBKP is disclosed in JP-A-10-245791.

[0035] The pulp that forms the ‘base paper produced for printing paper’used in the present invention preferably has (1) an average degree ofpolymerization of 800 or more, or gives (2) a pH on the base papersurface of 6.0 or more, or (3) an internal bond strength in the basepaper of 10 to 20 N-cm, and it is particularly preferable for theabove-mentioned requirements (1), (2) and (3) to be satisfiedsimultaneously.

[0036] Details of these characteristics are described in JP-A-3-149542(Japanese Registered Patent No. 2671154).

[0037] With regard to an additive that can be used in the ‘base paperproduced for printing paper’, it is preferable to use an additive thatis prepared so that it does not adversely affect the photographicproperties. That is to say, the additive that is used in the base paperis preferably an additive that does not adversely affect the raw stockstorability of photographic light-sensitive materials, storage stabilityof developed prints, etc.

[0038] Such an additive includes a sizing agent (a rosin, a higher fattyacid salt, an alkylketene dimer, an alkenyl succinate, etc.), a paperstrength increasing agent (polyacrylamide, etc.), a fixing agent(aluminum sulfate, etc.), a pH adjusting agent (sodium aluminate, sodiumhydroxide, etc.), a filler (clay, talc, calcium carbonate, etc.), andother additives (a dye, a slime control agent, etc.).

[0039] A base paper formed by using an amphoteric polyacrylamide(JP-A-59-31949) as a paper strength increasing agent is preferably usedin the present invention. A particularly useful paper strengthincreasing agent is an amphoteric polyacrylamide having an averagemolecular weight of 2,500,000 to 5,000,000, the average molecular weightbeing measured by gel permeation chromatography. The amphotericpolyacrylamide is an amphoteric copolymer obtained by copolymerizing ananionic monomer and a cationic monomer using as the main monomeracrylamide or methacrylamide (JP-A-6-167767). The base paper ispreferably a neutral paper that has been made in a neutral region inwhich the pH of the paper stock is in the range of 6.0 to 7.5. When thepH exceeds the above-mentioned range, the cellulose tends to be easilyhydrolyzed. When the cellulose forming the base paper undergoeshydrolysis, its molecular weight (degree of polymerization) decreases,thereby degrading the strength of the base paper. The use of a basepaper with a decreased molecular weight in the manufacture of paperresin pellets causes the problems that (1) the cellulose fibers easilyundergo thermal decomposition during molding; (2) the Izod impactstrength is degraded; (3) an acidic gas, etc. that adversely affectsphotographic properties is easily generated; and so on. It is thereforepreferable for the base paper to be made in the neutral region so thatthe paper surface has a pH of 6.0 to 7.5.

[0040] With regard to a polyolefin that is used for producing waterproofpaper for printing paper in which a polyolefin resin is laminated onboth sides of the above-mentioned base paper, a homopolymer of anα-olefin such as polyethylene and a copolymer of α-olefins arepreferred. Examples thereof include high-density polyethylene (HDPE),low-density polyethylene (LDPE), and a mixture thereof.

[0041] The molecular weight of these polyolefins is not particularlylimited as long as a white pigment or a fluorescent whitener can beincluded in the laminated layer formed by extrusion coating, but apolyolefin having a molecular weight in the range of 20,000 to 200,000is usually used.

[0042] The thickness of the polyolefin resin laminated layer ispreferably 15 to 50 μm.

[0043] When the α-olefin homopolymer contains an additive, the additiveis preferably one that does not adversely affect the raw stockstorability of light-sensitive materials, the storage stability ofdeveloped prints, etc. It is particularly preferable to include a whitepigment, a colored pigment, and an antioxidant in the polyolefin resinlaminated layer on the side on which a photographic emulsion would becoated.

[0044] A typical layer structure of the waterproof paper for printingpaper has, going from the front side on which the photographic emulsionwould be coated to the opposite side; an LDPE layer containing titaniumdioxide and zinc stearate, a base paper layer, and a mixed LDPE and HDPElayer containing calcium stearate. Typical basis weights are 21 to 32g/m² for the first LDPE layer, 135 to 167 g/m² for the base paper layer,and 23 to 24 g/m² for the second, mixed LDPE/HDPE layer.

[0045] The production of a paper resin in the present invention canemploy a base paper produced for printing paper but preferably employs awaterproof paper for printing paper in which the above-mentioned basepaper is laminated with a polyolefin resin.

[0046] With regard to an additional thermoplastic resin that can be usedin the present invention, there can be cited as preferable examplesthereof polyolefins such as polyethylene (PE) and polypropylene (PP);polyesters such as polyethylene terephthalate and polybutyleneterephthalate; polyamides such as nylon-6, nylon-6,6, nylon-11 andnylon-12; polystyrene; polystyrene copolymers, etc. In particular, apoly-α-olefin such as PE or PP, which has compatibility with apolyolefin resin that has been laminated on the base paper, ispreferably used as the additional thermoplastic resin. The ‘additionalthermoplastic resin’ referred to here denotes a separate thermoplasticresin from the polyolefin resin that has been laminated on the basepaper, and does not exclude a thermoplastic resin having the samecomposition as that of the polyolefin resin used for the base paperlamination.

[0047] Use of an elastomer resin as a component of the thermoplasticresin can give an elastic molded product.

[0048] In the molded product and the package of the present invention,the mixing ratio by weight of the paper-derived cellulose fibers to thetotal of the thermoplastic resins is 51:49 to 75:25, and preferably60:40 to 70:30.

[0049] When mixing an additional thermoplastic resin with a waterproofpaper for printing paper in which 75 parts by weight of the base paperis laminated with 25 parts by weight of a polyolefin resin, in order toensure that 51 wt % to 75 wt % of the molded product is formed from thebase-paper-derived cellulose component, 47 to 0 parts by weight of theadditional thermoplastic resin is added to 100 parts by weight of thewaterproof paper for printing paper.

[0050] The antioxidant that can be preferably used in the presentinvention is a hindered phenol antioxidant, and its melting point ispreferably at least 100° C., and particularly preferably at least 120°C.

[0051] Representative examples of the hindered phenols that can be usedin the present invention are listed below.

[0052] 1)1,3,5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

[0053] 2)tetrakis[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane,

[0054] 3) octadecyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate,

[0055] 4)2,2′,2′-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethylisocyanurate,

[0056] 5)1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,

[0057] 6) tetrakis(2,4-di-tert-butylphenyl) 4,4′-biphenylenediphosphiteester,

[0058] 7) 4,4′-thiobis(6-tert-butyl-o-cresol),

[0059] 8) tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,

[0060] 9) 2,2′-methylenebis(4-methyl-6-tert-butylphenol),

[0061] 10) 4,4′-methylenebis(2,6-di-tert-butylphenol),

[0062] 11) 4,4′-butylidenebis(3-methyl-6-tert-butylphenol),

[0063] 12) 2,6-di-tert-butyl-4-methylphenol,

[0064] 13) 4-hydroxymethyl-2,6-di-tert-butylphenol,

[0065] 14) 2,6-di-tert-butyl-4-n-butylphenol,

[0066] 15)2,6-bis(2′-hydroxy-3′-tert-butyl-5′-methylbenzyl)-4-methylphenol,

[0067] 16) 4,4′-methylenebis(6-tert-butyl-o-cresol),

[0068] 17) 4,4′-butylidenebis(6-tert-butyl-m-cresol),

[0069] 18)3,9-bis{1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane,

[0070] 19) 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane,

[0071] The amount of hindered phenol antioxidant added is 0.001 to 1.0wt % of the total of the paper and the thermoplastic resins, preferably0.005 to 0.8 wt %, more preferably 0.01 to 0.6 wt %, and most preferably0.02 to 0.4 wt %.

[0072] It is preferable to add thermoplastic resin pellets containing anantioxidant in a concentrated form by melt-kneading, and the pellets areadded to a mixture of the paper and the thermoplastic resins beforemolding at the latest. To elaborate, a desired amount thereof is addedas concentrated pellets to a material supply tank immediately beforemolding. Preferably, paper resin pellets, which will be described below,and concentrated antioxidant pellets are metered individually andsupplied to a hopper installed in a molding machine, and the mixture iskneaded and then molded.

[0073] The aldehyde-neutralizing agent used in the present invention isrepresented by general formula (I) below.

General Formula  (I)

[0074]

[0075] In the formula, R¹, R², and R³ denote divalent organic radicalsand together form a cyclic imino compound via covalent bondstherebetween.

[0076] It is surmised that, due to the high reactivity of the iminogroup, the active imino compound represented by general formula (I)reacts, as shown in reaction formula (II) below, with an aldehyde suchas furfural that is generated as a result of the thermal decompositionof cellulose in the paper resin, to form a methylol group.

R—NH—R′+HCHO→R(CH₂OH)—R′  (II)

[0077] In order for the imino group to have such a reactivity, it isessential for it to have a sufficiently low electron density and be ableto induce an electronic nucleophilic reaction. It is therefore necessaryfor the organic radicals that are directly chemically bonded to theimino group to be electrophilic. Such organic radicals bonded to theimino group, that is to say, organic radicals denoted by R¹ and R² inthe above-mentioned general formula (I), are preferably —CO—, —COO—,—NH—, —NH₂, a phenyl group, a biphenyl group, or a naphthalene group.

[0078] The aldehyde-neutralizing agent of the present invention ispreferably neither released from the molded product after the moltenmixing with the paper resin nor the cause of thermal decomposition.Preferable examples of the compound represented by general formula (I)include hydantoins and imidazoles, and hydantoins are preferred in thepresent invention.

[0079] As examples of the hydantoins, hydantoin, 5-isopropylhydantoin,5,5-dimethylhydantoin, 5,5-diphenylhydantoin and allantoin can be cited,but they are not limited thereto.

[0080] With regard to the antioxidant and the aldehyde-neutralizingagent that can be used in the present invention, compounds that aregenerally known as an ‘antioxidant’ or an ‘aldehyde-neutralizing agent’can be cited. Such antioxidants and neutralizing agents are describedin, for example, Zenjiro Osawa ed. ‘Degradation and Stabilization ofMacromolecular Materials (Kobunshizairyo no Rekka to Anteika)’ (May1990, Published by CMC), Motonobu Minagawa ed. ‘Plastic Additive UsageNotes (Plastic Tenkazai Katsuyo Note)’ Jul. 5, 1996, Published by KogyoChosa Kai.

[0081] A cyclic organic compound having an active imino grouprepresented by general formula (I) is added at 0.05 to 3.0 % wt of thetotal of the paper and the thermoplastic resins, preferably 0.06 to 2.0wt %, and particularly preferably 0.067 to 1.0 wt %.

[0082] The method and the timing of the addition are the same as thosein the case of the above-mentioned hindered phenol antioxidant.

[0083] It is preferable to add an antioxidant and analdehyde-neutralizing agent in combination to the molded product of thepresent invention. The amounts thereof added are the same as in the casewhere they are used singly. The antioxidant of the present invention isadded at at least 0.05 wt % and, in addition, when 5,5-dimethylhydantoinis used as the aldehyde-neutralizing agent, it is preferably added at atleast 0.05 wt %.

[0084] The thickness of the molded product of the present invention isfrom 0.5 mm to 10 mm, preferably from 0.5 mm to 5 mm, and morepreferably from 0.8 mm to 3 mm.

[0085] FIGS. 1 to 3 show embodiments of the molded product for alight-sensitive material in accordance with the present invention.

[0086]FIG. 1 shows an instant film pack, which is one embodiment of thepresent invention. The instant film pack includes a case main body 1, afilm cover 2, a light-shielding sheet 4, a light-shielding sheet 5, abase plate 6, and a flap 7. The above-mentioned components 1 to 6 employmolded resin products, and the molded products of the present inventioncan be used for a part or the whole of these components. The components,together with a film 3, can be made into a light-sensitive materialpackage.

[0087]FIG. 2 shows cushioning materials and a package, which areembodiments of the present invention, that are used to store a long rollof light-sensitive material disclosed in JP-A-11-327089. FIG. 2 (A) isan exploded perspective view of the package, and FIG. 2 (B) and FIG. 2(C) are perspective views of the cushioning material from differentdirections. The cushioning material 14 has a thickness of 1.5 mm, and isa molded product of the present invention.

[0088]FIG. 3 is a perspective view showing a case main body and a lidfor FUJICOLOR SUPERIA (registered trademark of Fuji Photo Film Co.,Ltd.) 400, which is one embodiment of the present invention.

[0089] In FIG. 2, the outermost periphery of a roll of light-sensitivematerial 11 is covered with a light-shielding sheet so that thelight-sensitive material is neither exposed to light nor damaged. Alight-shielding protecting plate 12 is fixed to a paper tube 11 a ateach of the two ends of the roll of light-sensitive material 11 in itswidth direction so that the ends are neither exposed to light nordamaged. When inserting the roll of light-sensitive material 11 into ahousing container 13, it is necessary to take care that the roll oflight-sensitive material is not deformed or broken due to a physicalshock such as a fall and that the roll of light-sensitive material isnot exposed to light as a result of breakage of the light-shieldingsheet or the protecting plate 12. The roll of light-sensitive material11 is therefore inserted into the housing container 13 while supportingopposite ends of the paper tube 11 a of the roll of light-sensitivematerial 11 by means of a pair of cushioning materials 14.

[0090] The cushioning material 14 is formed from a square substrate 14 amade of a synthetic resin, a side wall 14 b formed integrally on theouter periphery of the substrate 14 a, a large number of reinforcingribs 14 c and 14 d formed on both sides of the substrate 14 a in radialdirections and in directions that are orthogonal thereto, a cylindricalpart 14 e formed integrally on the central area of the substrate 14 aand having its forward end closed, and projections 14 f provided on thefour corners of the substrate 14 a so as to extend orthogonallytherefrom. Inserting the cylindrical part 14 e of the cushioningmaterial 14 into the paper tube 11 a supports the roll oflight-sensitive material 11.

[0091] The molded product for a light-sensitive material of the presentinvention can be produced by various methods. The molded product for alight-sensitive material of the present invention is characterized inthat a thermoplastic resin and a waterproof paper for printing paper, inwhich a base paper preferably produced for printing paper is laminatedwith a polyolefin, are used as starting materials, and it is molded sothat the component ratio by weight of the base-paper-derived cellulosefibers and the total of the thermoplastic resins is in the range of51:49 to 75:25 in the molded product for a light-sensitive material thatis finally obtained. The ‘total of the thermoplastic resins’ referred tohere denotes the total of the polyolefin resin that is laminated on thewaterproof paper for printing paper and all of the thermoplastic resinsthat are added during the production process. Setting the lower limit ofthe proportion of the cellulose fiber component at 51 wt % ensures thatthe cellulose fibers are present at more than 50 wt % of the wholeproduct.

[0092] With regard to the timing of the first addition of athermoplastic resin, a choice can be made as to whether or not a mixtureof cellulose fibers and a polyolefin resin, obtained by breaking thewaterproof paper for printing paper, is by itself temporarily made intopellets. An example of the process for producing a molded productwithout forming the above-mentioned pellets is illustrated below:

[0093] 1) A step in which a waterproof paper for printing paper, inwhich a base paper produced for printing paper is laminated with apolyolefin resin, is broken to give a mixture of cellulose fibers andthe polyolefin resin; 2) a step in which an additional thermoplasticresin, which may be molten, is added if necessary to the mixtureobtained above; and 3) a step in which a molded product for alight-sensitive material containing the base paper and the polyolefinresin is molded so that the component ratio by weight of thebase-paper-derived cellulose fibers to the total of the thermoplasticresins is in the range of 51:49 to 75:25.

[0094] An example of the process for producing a molded productinvolving making a mixture of cellulose fibers and a polyolefin resin,which is obtained by breaking the waterproof paper for printing paper,into pellets is illustrated below:

[0095] 1) A step in which a waterproof paper for printing paper, inwhich a base paper produced for printing paper is laminated with apolyolefin resin, is broken to give a mixture of cellulose fibers andthe polyolefin resin; 2) a step in which the mixture so obtained is byitself temporarily made into pellets, the pellets so obtained arere-broken, and the broken cellulose fibers and polyolefin resin arekneaded with an additional thermoplastic resin at the same time as there-breaking or separately; and 3) a step in which a molded product for alight-sensitive material containing the base paper and the polyolefinresin is molded so that the component ratio by weight of thebase-paper-derived cellulose fibers to the total of the polyolefin resinand the additional thermoplastic resin is in the range of 51:49 to75:25. This process is preferable since the compatibility of thecellulose fibers with the additional thermoplastic resin can beimproved.

[0096] The above-mentioned steps can be carried out in a continuoussequence or the mixture, etc. obtained in each of the steps can bestored temporarily. The antioxidant and the aldehyde-neutralizing agentof the present invention are preferably added in the above-mentionedstep 3).

[0097] A more detailed example of the process for producing a moldedproduct for a light-sensitive material of the present invention is asfollows.

[0098] Hereinafter, this production process example is called the‘detailed production process example’. In the examples explained below,this ‘detailed production process example’ will be referred to.

[0099] (1) A waterproof paper for printing paper, in which a base paperproduced for printing paper is laminated with a polyolefin resin, isroughly broken using a shearing machine. As one embodiment, it is cutinto 30×30 mm square pieces.

[0100] (2) The waterproof paper roughly broken in this way is fiberizedinto cellulose fibers in a torn flock form by the beating action of pinsusing a pin mill or a breaking action under friction using a refiner.

[0101] (3) The bulky flock-form mixture of the cellulose fibers and thepolyolefin resin is compression-kneaded using a pellet mill to givecompact pellets.

[0102] (4) The pellets obtained in the above-mentioned step aresubsequently broken using a turbo mill.

[0103] (5) An additional thermoplastic resin powder is added to themixture of cellulose fibers and polyolefin resin so broken, and they areagain kneaded to form pellets using a pellet mill.

[0104] (6) The pellets containing the cellulose fibers, the polyolefinresin, and the additional thermoplastic resin obtained in theabove-mentioned step are kneaded using an extruder to give paper resinpellets.

[0105] (7) The paper resin pellets thus obtained, concentratedantioxidant pellets, and concentrated aldehyde-neutralizing pellets aresupplied to an injection-molding machine and injection-molded into thedesired form.

[0106] The above-mentioned steps can be modified in a variety of ways.For example, in the above-mentioned breaking step (4) the pelletsobtained in step (3) and lumps of an additional thermoplastic resin maybe broken together to give a mixture. This mixture can be supplied tothe pellet mill in step (5).

[0107] It is surmised that, since the molded product for alight-sensitive material of the present invention uses a waterproofpaper for printing paper as a starting material, the broken polyolefinresin and the broken cellulose fibers are uniformly mixed in step (2),which employs a pin mill or a refiner. It is therefore possible toachieve good mixing of the cellulose fibers, the polyolefin resin, andan additional thermoplastic resin with each other during the subsequentsteps (3) to (5).

[0108] It is also possible to prepare the pellets in step (6) using anamount of thermoplastic resin that is smaller than the final amount thatis to be added, and the remainder of the thermoplastic resin is added inorder to mold a lining layer, etc. when injection-molding the moltenpellets. The number of steps in which the thermoplastic resin is addedand the amount thereof added can be chosen freely as long as theinjection molding is carried out so that the component ratio by weightof the base paper to the total of the thermoplastic resins in the moldedproduct is in the range of 51:49 to 75:25. The remainder of thethermoplastic resin can also be used for molding a lining layer bytwo-color molding or insert molding.

[0109] When the proportion of the base paper component exceeds 75 wt %,the injection pressure rapidly increases, thereby making it impossibleto carry out injection molding in a stable manner. This upper limit ismuch higher in the case where a waterproof paper for printing paper isused than is the case where cellulose fibers from recycled newspaper,etc. are used by themselves as a starting material.

[0110] In the kneading operation in step (5) of the above-mentioneddetailed production process example, the moisture content of thecellulose fibers that are kneaded with the thermoplastic resin ispreferably 5 wt % to 40 wt %, and more preferably 10 wt % to 20 wt %.Maintaining this moisture content can fully utilize theresin-reinforcing function of the cellulose fibers.

[0111] A refiner that can be used in the fiberizing step (2) of theabove-mentioned detailed production process example is explained below.

[0112]FIG. 4 shows cross sections of a stationary disc and a rotary discof one example of the refiner. FIG. 5 is a lateral cross section of oneexample of the refiner.

[0113] This step is a step for fiberizing the cellulose fibers of thepaper to break them into the flock-form cellulose fibers.

[0114] The refiner comprises a stationary disc 23 and a rotary disc 24.As shown in FIG. 4, the stationary disc 23 has stationary projections 25arranged in a line on coaxial circles A on one side of the disc and therotary disc 24 has moving projections 26 arranged on coaxial circles Bon one side of the disc, the coaxial circles B being positioned betweenthe coaxial circles A. As shown in FIG. 5, the above-mentionedstationary disc 23 and rotary disc 24 are made to face each other sothat the stationary projections 25 and the moving projections 26 meshwith each other.

[0115] In this state, rotating the rotary disc 24 around its centralaxis abrades WP paper (or recycled paper), etc. between the stationaryprojections 25 and the moving projections 26, thereby breaking thepaper.

[0116] In FIG. 5, 28 denotes a case and 27 denotes a mesh drum. Sincethe WP paper (or recycled paper) is broken by abrading it between thestationary projections 25 and the moving projections 26, the WP paper(or recycled paper) is kneaded and disentangled between the stationaryprojections 25 and the moving projections 26, thereby achievingsufficient fiberization while suppressing cutting of the fiber.

[0117] A turbo mill that can be used in step (4) of the detailedproduction process example is explained below.

[0118]FIG. 6 is a vertical longitudinal cross section of a turbo mill.FIG. 7 is a magnified cross section at line I-I in FIG. 6, which showsthe shape of a blade 31 having a triangular cross section and a rotor32.

[0119] 1) In the turbo mill as shown in FIG. 7, the inner face of thecylindrical blade 31 is provided with a large number of grooves 33having a triangular cross section, and the cylindrical surface of therotor 32 is provided with ridges 34.

[0120] 2) The large number of ridges 34 of the rotor 32 rotating at highspeed cause a flow of air around the outer circumference of the rotor32, the air flow having a high flow rate in the rotational direction ofthe rotor 32. This air flow is compressed when the tips of the ridges 34of the rotor 32 approach the grooves 33 provided on the inside of theblade 31, and the air flow is expanded when the tips of the ridges 34depart from the grooves 33, thereby causing high frequency pressurevibrations.

[0121] 3) In FIG. 6, pellets that are supplied through an inlet (notillustrated) are broken finely by the above-mentioned pressurevibrations.

[0122] 4) The pellets that have been finely broken by the turbo mill arecollected together with the air by a cyclone bag filter.

[0123] 5) Controlling the number of turbo mill treatments can achieve adesired fiber length.

[0124] A known kneading machine such as a pressure type kneader can beused for kneading.

[0125] Other preferable conditions for the kneading step are describedin JP-A-5-50427.

[0126] The kneading temperature is preferably from 90° C. to 220° C.,and particularly preferably from 140° C. to 170° C. When the kneadingtemperature is less than 90° C., the kneading tends to be insufficient.This tendency can be observed to some extent until the temperaturereaches 140° C. When the kneading temperature exceeds 220° C., since thecellulose easily decomposes, a large amount of components that willadversely affect the light-sensitive material are generated.

[0127] The light-sensitive material package comprises a molded productfor a light-sensitive material obtained by any one of theabove-mentioned processes and a light-sensitive material that is usedwith the molded product. In the case where the molded product for alight-sensitive material is a container, a light-sensitive material canbe housed therein to give a light-sensitive package.

[0128] In order to impart light-shielding performance to a paper resin,the addition of 0.05 to 25 wt % of a light-shielding material theretocan improve the light-shielding function that is required for a moldedproduct used on the periphery of a photographic light-sensitive materialwithout degrading the chemical and physical properties of the paperresin. When the amount is less than 0.05 wt %, light-shieldingperformance cannot be exhibited, which not only fails to achieve theobject of the addition but also increases the cost. When the amountexceeds 25 wt %, the physical strength is degraded and at the same timethe appearance becomes poor.

[0129] Examples of the light-shielding material that can be added inorder to introduce light-shielding performance are as follows:

[0130] (1) Inorganic compounds

[0131] A. Oxides

[0132] Silica, diatomaceous earth, alumina, titanium oxide, iron oxide,zinc oxide, magnesium oxide, antimony oxide, barium ferrite, strontiumferrite, beryllium oxide, pumicite, pumicite balloons, alumina fibers,etc.

[0133] B. Carbonates

[0134] Calcium carbonate, magnesium carbonate, dolomite, dawsonite, etc.

[0135] C. Silicates

[0136] Talc, clay, mica, asbestos, glass fiber, glass balloons, glassbeads, calcium silicate, montmorillonite, bentonite, etc.

[0137] D. Carbon

[0138] Carbon black, graphite, carbon fiber, hollow carbon spheres, etc.

[0139] E. Others

[0140] Iron powder, copper powder, lead powder, tin powder, stainlesssteel powder, pearl pigment, aluminum powder, molybdenum sulfide, boronfiber, silicon carbide fiber, yellow copper fiber, potassium titanate,lead titanate zirconate, zinc borate, barium metaborate, calcium borate,sodium borate, aluminum paste, etc.

[0141] (2) Organic compounds

[0142] Wood powder (pine, oak, sawdust, etc.), husk fiber (almond,peanut, chaff, etc.), various types of colored fiber such as cotton andjute, paper pieces, cellophane pieces, nylon fiber, polypropylene fiber,starch, aromatic polyamide fiber, etc.

[0143] There are various modes for preparing a light-shielding material,but a concentrated master batch method is preferable in terms of cost,prevention of contamination of the workplace, etc. JP-B-40-26196 (JP-Bdenotes Japanese examined patent application publication) discloses amethod for preparing a polymer-carbon black master batch by dispersingcarbon black in a solution of a polymer dissolved in an organic solvent,and JP-B-43-10362 discloses a method for preparing a concentrated masterbatch by dispersing carbon black in polyethylene. Pellets obtained bymixing a thermoplastic resin with 10 wt % of carbon black in aconcentrated manner can be used. A desired light-shielding performancecan be obtained by adding carbon black at about 0.5 wt % to the moldedproduct of the present invention.

[0144] With regard to the carbon black that is used in the moldedproduct for a light-sensitive material of the present invention, carbonblack having a pH of 6.0 to 9.0 and an average particle size of 10 to120 μm is preferred since fog is not caused in a light-sensitivematerial, changes in light sensitivity are suppressed, thelight-shielding ability is high, and the occurrence of pinholes due tothe formation of lumps of carbon black and fisheyes is suppressed evenwhen it is added to the resin composition in the present invention. Inparticular, furnace carbon black having a volatile component content of2.0% or less and an oil adsorption of 50 ml/100 g or more is preferred.Channel carbon black is expensive and tends to cause undesirable fog ina light-sensitive material. When its use is required, it should bechosen after examining its influence on the photographic properties.

[0145] Examples of preferable commercial products include Carbon black#20(B), #30(B), #33(B), #40(B), #44(B), #45(B), #50, #55, #100, #600 ,#2200(B), #2400, #950(B), MA8, MA11 and MA100 (all manufactured byMitsubishi Chemical Corp.).

[0146] As examples of commercial products available outside Japan, BlackPearls 2, 46, 70, 71, 74, 80, 81, 607, etc., Regal 300, 330, 400, 660,991, SRF-S, etc. Vulcan 3, 6, etc., and Sterling 10, SO, V, S, FT-FF,MT-FF, etc. (all manufactured by Cabot) can be cited. Furthermore,Printex-Alfa and Printex-90 (all manufactured by Degussa-Huls) can becited. However, they are not limited thereto.

[0147] The amount of light-shielding material added is usually 0.05 to25 wt % relative to the weight of the final molded product, preferably0.1 to 15 wt %, more preferably 0.5 to 10 wt %, and most preferably 1.0to 7.0 wt %.

[0148] Since the paper resin in the present invention has a low meltflow rate (MFR), a lubricant can be added as long as the effect of thepresent invention is not degraded.

[0149] The names of typical lubricants that can be used in the moldedproduct of the present invention and their manufacturers' names arelisted below.

[0150] (1) Silicone type lubricants

[0151] Various grades of dimethylpolysiloxane and modified compoundsthereof (Shin-etsu Silicone Co., Ltd., Toray Silicone, Inc.)

[0152] (2) Oleamide type lubricants

[0153] Armoslip CP (Lion Akzo), Neutron (Nippon Fine Chemical Co.,Ltd.), Neutron E-18 (Nippon Fine Chemical Co., Ltd.), Amido O (NittoChemical Industry Co., Ltd.), Alfro E:10 (NOF Corp.), Diamid O-200(Nippon Kasei Chemical Co., Ltd.), Diamid C-200 (Nippon Kasei ChemicalCo., Ltd.), etc.

[0154] (3) Erucamide type lubricants

[0155] Alfro-F-10 (NOF Corp.), etc.

[0156] (4) Stearamide type lubricants

[0157] Alfro-S-10 (NOF Corp.), Neutron 2 (Nippon Fine Chemical Co.,Ltd.), Diamid 200 (Nippon Kasei Chemical Co., Ltd.), etc.

[0158] (5) Bisfatty acid amide type lubricants

[0159] Bisamide (Nippon Kasei Chemical Co., Ltd.), Diamid 200 Bis(Nippon Kasei Chemical Co., Ltd.), Armowax BBS (Lion Akzo), etc.

[0160] (6) Nonionic surfactant type lubricants

[0161] Electrostripper TS-2, Electrostripper-TS-3 (Kao Corp.), etc.

[0162] (7) Hydrocarbon type lubricants

[0163] Liquid paraffin, natural paraffin, microwax, synthetic paraffin,polyethylene wax, polypropylene wax, chlorinated hydrocarbons,fluorocarbons.

[0164] (8) Fatty acid type lubricants

[0165] Higher fatty acids (preferably those having 12 carbons or more),oxyfatty acids.

[0166] (9) Ester type lubricants

[0167] Lower alcohol esters of fatty acids, polyhydric alcohol esters offatty acids, polyglycol esters of fatty acids, fatty alcohol esters offatty acids

[0168] (10) Alcohol type lubricants

[0169] Polyhydric alcohols, polyglycols, polyglycerols.

[0170] (11) Metallic soaps

[0171] Compounds of a higher fatty acid such as lauric acid, stearicacid, ricinoleic acid, naphthenic acid or oleic acid and a metal such asLi, Mg, Ca, Sr, Ba, Zn, Cd, Al, Sn or Pb.

[0172] Preferred embodiments of the molding method of the presentinvention are listed below.

[0173] 1) Relationship between the photographic properties and thecylinder temperature when molding

[0174] When using paper resin pellets in the present invention, there isa tendency for the cellulose component forming the paper resin pelletsto undergo thermal decomposition when molding, thereby causingdegradation in the photographic properties, and it is thereforepreferable for the molding temperature to be as low as possible. Fromthe results of examining the relationship between the cylindertemperature and the photographic properties, it is desirable for thecylinder temperature to be 180° C. or less, preferably 170° C. or less,and more preferably in the range of 150° C. to 170° C.

[0175] 2) Relationship between the moldability and the MFR of a resinthat is added to the paper resin pellets

[0176] Since the paper resin pellets produced from a WP paper have acomparatively long fiber length, the moldability is poor. When theflowability of the resin that is added thereto is poor, short shotmolded products are formed. As a result of an investigation by thepresent inventors, taking the extent of sink marks in the molded product(indentations in the molded product) into consideration, the MFR of theresin that is added is preferably at least 15 g/10 min., more preferablyat least 30 g/10 min., and most preferably 45 to 80 g/10 min.

[0177] With regard to the molded products for light-sensitive materialsof the present invention, there are, for example, a moisture-proofcontainer and its associated member for photographic color paper and, inparticular, a moisture-proof container and its component member housinga light-shielding container (cartridge) for photographic film, aninstant film pack shown in FIG. 3 (0.9 mm thick black container forinstax mini (registered trade name) card size instant film by Fuji PhotoFilm Co., Ltd.), and a moisture-proof container (including a cover)shown in FIG. 3 for a 135 format film cartridge. In addition, the moldedproduct of the present invention can be used as a 135 format spool, acartridge for an APS format film, a 110 format film cartridge, acuboid-shaped cartridge housing a light-sensitive material for printing,a paper tube around which a long length of light-sensitive material iswound, a flange for winding up a long length of light-sensitive materialand retaining the opposite sides thereof, a cushioning material that isplaced in a container for a light-sensitive material, supporting boardfor a light-sensitive material laminate (a package or a part thereofthat is in contact with a light-sensitive material laminate), a filmcontainer equipped with a lens (registered trademark ‘Utsurundesu’ ofFuji Photo Film, Co., Ltd.), etc.

[0178] The molded product of the present invention does not degrade thephotographic properties and has excellent mechanical properties.Furthermore, the proportion of cellulose fibers in the molded productexceeds 50 wt %, and the product can therefore be disposed of with alower burden on the environment.

[0179] Refuse from uncoated printing paper generated in the process forthe production of printing paper, etc. can be effectively recycled togive a light-sensitive material package or a functional component.

[0180] Molding at a cylinder temperature of as low as about 170° C.using an antioxidant and an aldehyde-neutralizing agent can give acontainer having a good storage performance so that it does not degradethe photographic properties of a light-sensitive material that is housedtherein.

EXAMPLES

[0181] Specific examples of the present invention are explained belowtogether with comparative examples, but they are not intended to limitthe present invention.

Example 1

[0182] In accordance with the above-mentioned detailed productionprocess example, an instax mini (registered trademark of Fuji Photo FilmCo., Ltd.) case was produced. Paper refuse of a waterproof paper forprinting paper formed by laminating 25 wt % of PE on both surfaces of 75wt % of a base paper for printing paper were roughly broken, thenfiberized by means of a refiner, temporarily made into pellets, and thenbroken by means of a turbo mill. A concentrated carbon black masterbatch and HDPE were added thereto to give paper resin pellets.Concentrated antioxidant pellets and concentrated neutralizing agentpellets were added to the paper resin pellets, and an instax mini casewas injection molded with a molding thickness of 0.8 mm.

[0183] As the antioxidant, Adeka Stab AO-30(1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane) from Asahi DenkaKogyo K.K. was used. As the neutralizing agent, 5,5-dimethylhydantoinmanufactured by Mitsui Chemicals Inc. was used.

[0184] The ratio by weight of the paper-derived cellulose fibers to thetotal of the thermoplastic resins, the amounts of the antioxidant andthe neutralizing agent added, and the molding temperature were changedas shown in Table 1 to give Samples A to J. Other production conditionsare described below. TABLE 1 Example Sample B C D E F Ratio by weight51:49 51:49 60:40 70:30 75:25 Cellulose fiber:resin Weight-average fiber0.3 0.3 0.3 0.3 0.3 length (mm) Antioxidant (wt %) 0.3 0.6 0.3 0.3 0.3Aldehyde-neutralizing 0.3 0.6 0.3 0.3 0.3 agent (wt %) Cylindertemperature (° C.) 170 170 170 170 170 Example Comparative Sample H I JA G Ratio by weight 51:49 51:49 51:49 51:49 80:20 Cellulose fiber:resinWeight-average fiber 0.3 0.3 0.3 0.3 0.3 length (mm) Antioxidant (wt %)0.3 0.3 0.3 0 0.3 Aldehyde-neutralizing 0.3 0.3 0.3 0 0.3 agent (wt %)Cylinder temperature (° C.) 180 190 200 170 170

[0185] An overall evaluation of the above-mentioned samples was carriedout based on the feasibility of molding (injection pressure), thecharring when molding, the photographic properties, the appearance ofthe molded product, etc. The results are given in Table 2.

[0186] The photographic properties were evaluated by measuring thechange (ΔD_(max)) in fog density. ΔD_(max) is the value obtained fromthe equation ΔD_(max)=M_(b)−M_(t). M_(t) is the highest blue densitywhen an instax mini light-sensitive material manufactured by Fuji PhotoFilm Co., Ltd. was loaded into each of the Cases A to J, hermeticallysealed, stored at 50° C. and 60% RH for 3 days, and then developed by astandard method. M_(b) is the value obtained when the above-mentionedlight-sensitive material was stored in a case made of a thermoplasticresin and hermetically sealed. The same applies to Examples 2 and 3.TABLE 2 Sample A B C D E Injection pressure (MPa) *1 6.5  6.5  6.5  6.8 7.5  Charring when molding *2 C A A A A Photographic properties 0.180.11 0.10 0.11 0.12 ΔD_(max) Appearance of molded A A B A A product *3Effect of antioxidant *4 C A A A A Effect of aldehyde- C A A A Aneutralizing agent *5 Overall evaluation *6 C A A/B A A Sample F G H I JInjection pressure (MPa) *1 8.4  9.1  6.3  6.0  5.7  Charring whenmolding *2 A — A B B Photographic properties 0.13 — 0.13 0.20 0.22ΔD_(max) Appearance of molded A — A B B product *3 Effect of antioxidant*4 A — A B B Effect of aldehyde- A — A B B neutralizing agent *5 Overallevaluation*6 A C A B B

[0187] The following points were found from the above-mentioned results.

[0188] (1) When the component ratio by weight of the paper-derivedcellulose fibers to the total of the thermoplastic resins exceeds 75:25,the injection pressure becomes too high for molding.

[0189] (2) Adding the antioxidant and the aldehyde-neutralizing agent at0.01 to 0.5 wt % can suppress the thermal decomposition of cellulosefibers.

[0190] (3) When the amounts of the antioxidant and thealdehyde-neutralizing agent added exceed 0.5 wt %, the appearancebecomes poor.

Example 2

[0191] 1) As a starting material a waterproof paper for printing paperwas used that had been formed by laminating a polyolefin resin on a basepaper produced for printing paper using hardwood bleached kraft pulp(LBKP) having a weight-average fiber length of 0.7 mm measured using anFS-100 measuring machine manufactured by Kajaani Co.

[0192] This waterproof paper for printing paper was formed by laminating25 parts by weight of a PE resin on 75 parts by weight of the basepaper.

[0193] 2) The waterproof paper for printing paper was roughly broken bymeans of a shearing machine.

[0194] 3) The waterproof paper roughly broken in this way was brokenusing a pin mill into cellulose fibers in a torn flock state.

[0195] 4) The highly bulky flock-state cellulose fibers werecompression-kneaded using a pellet mill to give pellets.

[0196] 5) 100 parts by weight of the pellets so obtained were mixed with52 parts by weight of ldemitsu Petroleum PJ68083HP PP resin, 0.2 wt % ofAdeka Stab AO-30 (1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane)from Asahi Denka Kogyo K.K. as the antioxidant, 0.2 wt % of5,5-dimethylhydantoin manufactured by Mitsui Chemicals, Inc. as theneutralizing agent, and 0.5 wt % of carbon black #950 from MitsubishiChemical Corp. to give a sample.

[0197] 6) The sample was broken using the above-mentioned turbo-millwhile changing the number of treatments as shown in Table 3.

[0198] 7) The sample so broken was kneaded and granulated in an extruderat a cylinder temperature of 170° C. to give paper resin pellets.

[0199] 8) An instant film pack having a thickness of 1 mm was moldedusing each of the paper resin pellet samples to give a pack sample. Themolding conditions, etc. were as follows: a Sumitomo Heavy Industries,Ltd. SG180 molding machine was used, the resin temperature was 170° C.,and the mold temperature was 70° C.

[0200] 9) The maximum injection pressure when molding, theweight-average fiber length of the cellulose in the molded product, thedrop strength, and the photographic properties when combined with aninstant film were evaluated. The evaluation results are given in Table3. TABLE 3 Sample No. K L M N O Number of turbo-mill 0 1 2 3 4treatments (times) Fiber length (mm) 0.6 0.5 0.4 0.3 0.2 Drop strength*1 A A A A B Photographic properties 0.10 0.11 0.11 0.11 0.18 ΔD_(max)Maximum injection 9.2 7.0 6.5 6.0 5.8 pressure (MPa) Overall evaluation*2 B A A A B

[0201] The following points were found from the above-mentioned results.

[0202] (1) The weight-average fiber length depends on the number ofturbo-mill treatments.

[0203] (2) When the weight-average fiber length exceeds 0.5 mm, thecompartibility with a resin drops, and the flowability of the paperresin when molding degrades, thereby causing short shots.

[0204] (3) When the weight-average fiber length is less than 0.3 mm, thecellulose easily undergoes thermal decomposition to form aldehydes,thereby degarding the photographic properties.

Example 3

[0205] Paper resin pellets were obtained as in Example 2 except that theamoount of neutralizing agent added was changed as shown in Table 4 andafter one treatment with a turbo-mill the treatment with an extruder wascarried out.

[0206] An instant film pack was molded using the above-mentioned paperresin pellets under the same molding conditions as in Example 2. Theodor due to trace amounts of aldehyde generated by thermal decompositionwhen molding, and the photogaphic properties after loading a film wereevaluated.

[0207] The evaluation of the odor was carried out by 10 randomly chosenpanelists using the evaluation criteria below, and is given as anaverage value.

[0208] The molded product samples were named F to L. Intensity of odorStrength of sensation of odor 5 No odor 4 Very slight sensation of odor(detection threshold) 3 Easily sensed odor 2 Obvious sensation of odor 1Strong odor 0 Unbearably strong odor

[0209] When the odor level is 4 or above, there is no problem inpractice. TABLE 4 Sample No. P Q R S T U V Amount of 0.00 0.01 0.03 0.100.20 0.30 0.40 neutralizing agent added (wt %) Photographic 0.10 0.090.02 0.01 0.009 0.009 0.009 properties ΔD_(max) Odor 1 4 4 5 5 5 5Overall evaluation *1 C B B A A A B

Example 4

[0210] The cases for housing photographic film shown in FIG. 3 weremolded by an injection molding method in the same manner as in Example 1to give the samples shown in Table 5. The thickness of the cases forhousing photographic film was 0.8 mm. The molding was carried out usinga Sumitomo Heavy Industries, Ltd. SG180 molding machine at a cylindertemperature of 170° C. For both Sample Nos. 1 and 2, molding of the caseemployed a base paper having a weight-average fiber length of thecellulose fibers after breaking of 0.3 mm. The ratio by weight of thecellulose fibers to the total of the thermoplastic resins in the moldedproduct was 51:49, the antioxidant content was 0.3 wt %, and thealdehyde-neutralizing agent content was 0.3 wt %.

[0211] The photographic properties were evaluated by measuring thechange (ΔD_(min)) in fog density. ΔD_(min) is the value obtained fromthe equation ΔD_(min)=M_(t)−M_(b). M_(t) is the lowest blue density whena negative color film SUPERIA 400 manufactured by Fuji Photo Film Co.,Ltd. was housed in case 1 or case 2, hermetically sealed, stored at 50°C. and 60% RH for 3 days, and then developed by a standard method. M_(b)is the value obtained when the above-mentioned film was housed in a casemade of a thermoplastic resin and hermetically sealed. TABLE 5 MFRInjection Photographic No. (g/10 min.) pressure (MPa) properties ΔDminMoldability *3 1 20 *1 7.6 0.01 A 2 40 *2 6.0 0.01 A

Example 5

[0212] In accordance with the above-mentioned detailed productionprocess example, a reinforcing rib in the cushioning material shown inFIG. 2 was produced. Paper refuse of a waterproof paper for printingpaper formed by laminating 25 wt % of PE on both surfaces of 75 wt % ofa base paper for printing paper were roughly broken, then fiberized bymeans of a refiner, temporarily made into pellets, and then broken bymeans of a turbo mill. A concentrated carbon black master batch and HDPEwere added thereto to give paper resin pellets. Concentrated antioxidantpellets and concentrated neutralizing agent pellets were added to thepaper resin pellets, and reinforcing ribs were injection molded to givethe molding thicknesses shown in Table 6. A Sumitomo Heavy Industries,Ltd. SG75 molding machine was used.

[0213] As the antioxidant, Adeka Stab AO-30(1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane) from Asahi DenkaKogyo K.K. was used. As the neutralizing agent, 5,5-dimethylhydantoinmanufactured by Mitsui Chemicals, Inc. was used.

[0214] The ratio by weight of the paper-derived cellulose fibers to thetotal of the thermoplastic resins, the amounts of the antioxidant andthe neutralizing agent added, and the molding temperature were changedas shown in Table 6. TABLE 6 Embodiment Sample 3 4 5 6 7 Ratio by weight51:49 51:49 51:49 51:49 51:49 Cellulose fiber:resin Weight-average fiber0.3 0.3 0.3 0.3 0.3 length (mm) Antioxidant (wt %) 0 0.1 0 0.1 0.1Aldehyde-neutralizing 0 0.1 0 0.1 0.1 agent (wt %) Cylinder temperature(° C.) 170 170 170 170 170 Thickness of 1.0 1.0 1.5 1.5 5 reinforcingrib (mm)

[0215] An overall evaluation of the above-mentioned samples was carriedout based on the feasibility of molding, the charring when molding, thephotographic properties, the appearance of the molded product, etc. Theresults are given in Table 7.

[0216] The photographic properties were evaluated by measuring thechange (ΔD_(min)) in fog density. ΔD_(min) is the value obtained fromthe equation ΔD_(min)=M_(t)−M_(b). M_(t) is the lowest blue density whena light-sensitive printing material S-FA100 manufactured by Fuji PhotoFilm Co., Ltd. was housed in cases using each of the cushioningmaterials 3 to 7, hermetically sealed, stored at 50° C. and 60% RH for 3days, and then developed by a standard method. M_(b) is the valueobtained when the above-mentioned light-sensitive printing material washoused in a case made of a thermoplastic resin and hermetically sealed.TABLE 7 Sample 3 4 5 6 7 Moldability *1 B B B B B Charring when molding*2 B B B B B Photographic properties 0.05 0.01 0.03 0.00 0.01 ΔD_(min)Appearance of molded B B C B B product *3 Effect of antioxidant *4 C B CB B Effect of aldehyde- C B C B B neutralizing agent *5 Drop test*6 B BB B B Overall evaluation *7 C B C A A

[0217] Although embodiments of the present invention have been explainedabove, the present invention is not limited by the above-mentionedembodiments, and the present invention can be modified in a variety ofways without departing from the spirit and scope of the appended claims.

Example 6

[0218] Instax mini cases B′ to J′ were produced the same way as Sample Bto J in Example 1, except that 2,6-di-tert-butyl-4-n-butylphenol wasused the same mole instead of1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane and that5,5-diphenylhydantoin was used the same mole instead of5,5-dimethylhydantoin. The instax mini cases showed good results similarto the results summarized in Table 2.

What is claimed is:
 1. A molded product for a light-sensitive materialhaving a component ratio by weight of paper-derived cellulose fibers tothe total of thermoplastic resins in the range of 51:49 to 75:25,comprising: at least one antioxidant; and at least onealdehyde-neutralizing agent.
 2. The molded product for a light-sensitivematerial according to claim 1, wherein the antioxidant comprises ahindered phenol antioxidant at 0.01 to 0.5 wt % of the molded product.3. The molded product for a light-sensitive material according to claim1, wherein the aldehyde-neutralizing agent comprises a hydantoincompound at 0.05 to 0.5 wt % of the molded product.
 4. The moldedproduct for a light-sensitive material according to claim 1, wherein thecomponent ratio by weight of the cellulose fibers to the total of thethermoplastic resins is in the range of 51:49 to 75:25, the cellulosefibers having a weight-average fiber length in the range of 0.30 mm to0.50 mm after breaking a base paper made from kraft pulp.
 5. The moldedproduct for a light-sensitive material according to claim 1, wherein themolded product has a thickness of 0.5 mm to 10 mm.
 6. The molded productfor a light-sensitive material according to claim 1, wherein the moldedproduct comprises a base paper and a polyolefin resin and is made by aprocess comprising steps of: breaking a waterproof paper for printingpaper, the waterproof paper being obtained by laminating a base paperproduced for printing paper with a polyolefin resin, to give a mixtureof cellulose fibers and the polyolefin resin; adding an additionalthermoplastic resin to the mixture if necessary; and molding so that theratio by weight of the base-paper-derived cellulose fibers to the totalof the polyolefin resin and the additional thermoplastic resin is in therange of 51:49 to 75:25.
 7. A light-sensitive material packagecomprising: a molded product for a light-sensitive material; and alight-sensitive material that is used with the molded product, themolded product for a light-sensitive material having a component ratioby weight of paper-derived cellulose fibers to the total ofthermoplastic resins in the range of 51:49 to 75:25 and comprising atleast one antioxidant and at least one aldehyde-neutralizing agent. 8.The light-sensitive material package according to claim 7, wherein theantioxidant comprises a hindered phenol antioxidant at 0.01 to 0.5 wt %of the molded product.
 9. The light-sensitive material package accordingto claim 7, wherein the aldehyde-neutralizing agent comprises ahydantoin compound at 0.05 to 0.5 wt % of the molded product.
 10. Thelight-sensitive material package according to claim 7, wherein thecomponent ratio by weight of the cellulose fibers to the total of thethermoplastic resins in the molded product is in the range of 51:49 to75:25, the cellulose fibers having a weight-average fiber length in therange of 0.30 mm to 0.50 mm after breaking a base paper made from kraftpulp.
 11. The light-sensitive material package according to claim 7,wherein the molded product has a thickness of 0.5 mm to 10 mm.
 12. Thelight-sensitive material package according to claim 7, wherein themolded product comprises a base paper and a polyolefin resin and is madeby a process comprising steps of: breaking a waterproof paper forprinting paper, the waterproof paper being obtained by laminating a basepaper produced for printing paper with a polyolefin resin, to give amixture of cellulose fibers and the polyolefin resin; adding anadditional thermoplastic resin to the mixture if necessary; and moldingso that the ratio by weight of the base-paper-derived cellulose fibersto the total of the polyolefin resin and the additional thermoplasticresin is in the range of 51:49 to 75:25.
 13. A process for producing amolded product for a light-sensitive material comprising, in thefollowing order, steps of: mixing a thermoplastic resin having a meltflow rate of at least 15 g/10 min. with pellets formed by breaking,compressing and granulating a base paper produced for printing paper, sothat the component proportions are 51 to 75 parts by weight ofpaper-derived cellulose fibers and 49 to 25 parts by weight of the totalof the thermoplastic resins; and molding the mixture with a moldingmachine at a cylinder temperature of 180° C. or less.
 14. The processfor producing a molded product for a light-sensitive material accordingto claim 13, wherein the melt flow rate is at least 30 g/10 min.
 15. Theprocess for producing a molded product for a light-sensitive materialaccording to claim 13, wherein concentrated antioxidant pellets andconcentrated aldehyde-neutralizing agent pellets are supplied to themolding machine together with the paper resin pellets.